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Three-helix-bundle Protein in a Ramachandran Model

Anders Irbäck·Fredrik Sjunnesson·Stefan Wallin
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Abstract

We study the thermodynamic behavior of a model protein with 54 amino acids that forms a three-helix bundle in its native state. The model contains three types of amino acids and five to six atoms per amino acid and has the Ramachandran torsional angles $ϕ_i$, $ψ_i$ as its degrees of freedom. The force field is based on hydrogen bonds and effective hydrophobicity forces. For a suitable choice of the relative strength of these interactions, we find that the three-helix-bundle protein undergoes an abrupt folding transition from an expanded state to the native state. Also shown is that the corresponding one- and two-helix segments are less stable than the three-helix sequence.

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Anders Irbäck, Fredrik Sjunnesson, Stefan Wallin. 2000-11-05. Three-helix-bundle Protein in a Ramachandran Model. https://doi.org/10.1073/pnas.240245297

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